1. Field of the Invention
The present invention relates to an image processing apparatus. In particular, the present invention relates to an image processing apparatus that is capable of executing printing with a spot color recording material and is capable of, prior to executing the printing, three-dimensionally previewing an output image in a virtual space.
2. Description of the Related Art
A conventional image processing apparatus can capture drawing data supplied from a host computer and forms an image based on the drawing data. The image processing apparatus uses an electrophotographic method, for example. In such an electrophotographic printing apparatus, a charging device chares a photosensitive drum to form an electrostatic latent image on the photosensitive drum with write light corresponding to image data. A developing device causes toner to adhere to the electrostatic latent image to develop the electrostatic latent image with the toner, thereby forming a visible image. Then, the toner image is transferred from the photosensitive drum to a sheet of paper and is fixed to the sheet with heat and pressure.
In the electrophotographic image processing apparatus, toners of cyan, magenta, yellow, and black (CMYK) are used as basic print colors called process colors. In addition, a toner of transparent color as a spot color recording material is applied to a part or the whole of a print image (see, e.g., Japanese Patent Application Laid-Open No. 2006-251722).
The spot color recording material includes, for example, green, orange, gold, silver, and transparent toners other than the CMYK toners.
In particular, the transparent toner is a transparent recording material with a characteristic for adding an image with transparency. With the transparent toner, specific textures such as gloss, luster, and mat can be expressed unlike printing using only the color toners.
For example, Japanese Patent Application Laid-Open No. 2008-145784 discusses an apparatus that provides in advance a preview of a printed product prior to printing using a spot color recording material. In the apparatus discussed in Japanese Patent Application Laid-Open No. 2008-145784, when print data is printed with a spot color recording material, a portion to be printed out with the spot color recording material is detected in advance, and the detected portion is displayed as a preview with a specific color or pattern.
Further, in the apparatus discussed in Japanese Patent Application Laid-Open No. 2008-145784, the preview display of the spot color recording material can be switched among the settings of off/auto/designated color. In the off-setting, the preview is not displayed. In the auto setting, such a function is provided to detect a color of a portion to which the spot color recording material is applied and to display the preview of a color different from the color of that portion as a spot-color portion. In the designated-color setting, a position to which the spot color recording material is applied is displayed with a color designated by a user.
In the case of printing using a spot color recording material, if an effect obtained by using the spot color recording material is constant (solid coloring of green or orange as a spot color), the preview for expressing the portion with the spot color recording material applied can be performed according to a method discussed in Japanese Patent Application Laid-Open No. 2008-145784. More specifically, if the portion with the spot color recording material applied is displayed with a specific color or pattern as in portions 101, 102, and 103 illustrated in FIG. 1, a user can totally imagine the finishing of printing. When printing is performed with a transparent toner, which has recently been released in the market, the light reflectance on the surface of a printed product can be changed. With such a characteristic of the transparent toner, a watermark pattern can be applied to the printed product, or a graphic effect with the texture can be produced.
In a preview for checking the finishing of a printed product by the user prior to printing with the spot color recording material whose light reflectance changes, the following preview method can be used. More specifically, in a window 401 illustrated in FIG. 4, a virtual light source and a virtual printed product are arranged in a virtual three-dimensional space. The user can freely rotate the virtual printed product via a mouse as illustrated in windows 501, 502, and 503 in FIG. 5, so that there can be considered a preview method for obtaining the texture with light reflection (referred to as “reflection of a light source”) with respect to the virtual printed product set in the virtual space.
The preview method for the virtual printed product appearing in the virtual space with light received from the virtual light source is referred to as a “three-dimensional preview” below.
However, in providing the three-dimensional preview, a method for adjusting the degree of occurrence of the reflection of a light source by the user may be troublesome to easily check the texture of a region to be printed with the spot color recording material on the virtual printed product. Thus, when the user rotates the virtual printed product in the preview via the mouse, it is difficult for the user to preview the virtual printed product while optimally adjusting the reflection of a light source.
Therefore, as illustrated in a window 601 in FIG. 6, the amount of reflection of the virtual light source to the virtual printed product may be excessively large depending on the setting of the virtual light source. Thus, the preview may make it difficult for the user to check a portion to be previewed. It is hence difficult for the user to recognize how the reflection of a light source is adjusted to accomplish the easiest preview display.